Disregarding the Android Market, which most Android users have in order to get apps in the first place, Facebook is the most popular Android app among adult smartphone owners in the US. That's right: Facebook is beating out all other apps on Android, including the ones made by Google.

The latest data comes from Nielsen, which ranked mobile apps by active reach: the percentage of Android owners who used the app within the past 30 days. The metrics research firm analyzed usage data from its proprietary device meters put on the smartphones belonging to thousands of participating consumers.

As you can see in the chart above, Nielsen broke down users by age group. Facebook had an 80 percent active reach for 18-24 year-olds, 81 percent for 25-34 year-olds, and 77 percent for 35-44 year-olds. In all three categories, the other apps in the top five were from Google (again, I'm excluding the Android Market): Google Search, Gmail, Google Maps, and YouTube. After the top five, all the other apps not only vary much more by age group, but they also have a noticeably lower reach.